I agree that keeping it out of the conference itinerary is probably best. I have only been to Pycon/PyconCA 2012, 2013 and will be speaking at 2014. I don't recall there being an official, sponsored event at a bar. There were provided areas for impromptu talk sessions and meetups (to hack or play board games or whatever). But overall it seemed like drinking was something that was scheduled unofficially for those interested in partaking after the day was over.
It might help trying out different communities. I know in Toronto the Ruby group frequently meets up for... drinks [0]. And I worked for a company that sponsored a few javascript meetups... and provided drinks. At least in Toronto there's a strong link between the Ruby/JS community and going out for beers. The Python and Lisp groups tend to meetup at co-working spaces and cafes.
[0] https://twitter.com/torontorb (just count the number of times "drinkup" is mentioned... I never even realized this was a thing until I read this article [1] http://createsend.com/t/j-72A1831D965A5352 One of many Toronto javascript events organized at a bar.